Dendrimer-based nanoscopic sponges and metal composites

ABSTRACT

Dendritic polymer based networks consisting of well-defined hydrophilic and oleophilic (i.e., hydrophobic) domains, are capable of performing as nanoscopic sponges for electrophilic guest moieties such as (i) inorganic and organic cations; (ii) charged or polarized molecules containing electrophilic constituent atoms or atomic groups; and (iii) other electrophilic organic, inorganic, or organometallic species. As a result of such performance, the networks yield novel nanoscopic organo-inorganic composites which contain organosilicon units as an integral part of their covalently bonded matrix.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is related to a prior copending application Ser. No.08/867,143, filed Jun. 2, 1997, now U.S. Pat. No. 5,739,218, entitled"Radially Layered Copoly (Amidoamine-Organosilicon) Dendrimers",assigned to the Dow Corning Corporation and the Michigan MolecularInstitute. This application is also related to another prior copendingapplication Ser. No. 08/897,943, filed Jul. 21, 1997, pending entitled"Dendrimer-Based Networks Containing Lyophilic Organosilicon andHydrophobic Polyamidoamine Nanoscopic Domains", also assigned to the DowCorning Corporation and the Michigan Molecular Institute. These priorcopending applications are referred to hereinafter as the '143application and the '943 application, respectively.

FIELD OF THE INVENTION

This invention is directed to covalently crosslinked dendrimer networkscontaining nanoscopic hydrophilic domains for complexation andencapsulation of metals, metal ions, metal oxides, metal sulfides, othermetal salts, or water soluble organic and organometallic molecules.

BACKGROUND OF THE INVENTION

The idea that dendrimers may function as robust, covalently bonded, andsurface enclosed nanoscopic encapsulators for smaller moieties includingorganic molecules and inorganic ions, has attracted considerableattention. Based on results from dilute solution viscometry ofpoly(amidoamine) (PAMAM) dendrimers, it was hypothesized by D. A.Tomalia et al in the Journal of the American Chemical Society, Volume109, Pages 1601-1603, (1987), that the intramolecular density ofdendrimers with symmetrical branch cells should decrease with the radialdistance from the core until a minimum is reached at certain generationsabove which the trend would reverse, and that the intramoleculardendrimer density would start increasing with the dendrimer radius inouter layers of these macromolecules.

Subsequent experiments with various dendrimers revealed that thishypothesis may have been accurate, and that dendrimers may in fact beglobular nanoscopic entities of (i) relatively soft and spongy interiorscapable of hosting smaller guest molecules, and (ii) a dense outer shellpenetrable for small molecules such as solvents or classical organicand/or inorganic reagents but impenetrable to large molecules such ashigh molecular weight macromolecules, other dendrimers, or their parts;i.e., P. R. Dvornic et al, Polymeric Materials Science & Engineering,Volume 77, Pages 116-117, (1997).

For example, it was shown that poly(amidoamine) dendrimers canencapsulate Cu²⁺ cations by complexing the cations into the interiordepending upon the pH, i.e., M. F. Ottaviani et al, in the Journal ofthe American Chemical Society, Volume 116, Pages 661-671, (1994); andthat after modification of the dendrimer surface by hydrophobes, thesecomplexes become soluble in organic solvents such as toluene, whereasCu²⁺ cations are otherwise not soluble, i.e., Y. Sayed-Sweet et al,Journal of Materials Chemistry, Volume 7(7), Pages 1199-1205, (1997).

It has also been shown that (i) poly(propyleneimine) (PPI) dendrimersmay function as molecular boxes for smaller organic molecules such asdyes and radicals, i.e., J. F. G. A. Jansen et al, in Science, Volume266, Pages 1226-1229, (1994); that (ii) so-called arborols may berendered chemically reactive to bind in their interior other reagentssuch as o-carborane delivered from their exterior, i.e., G. R. Newkomeet al, in Angew. Chem. Int. Ed. Engl., Volume 33, Pages 666-668, (1994);and that (iii) PAMAM dendrimers may serve as inert, confined, nanoscopicreactors, for polymerization reactions if both the monomer or monomersand the initiator are delivered into and enclosed within theirinteriors, i.e., V. U. Wege et al, in Polymer Preprints, Volume 36,Number 2, Pages 239-240, (1995).

However, these references refer to results obtained using exclusivelypure dendrimers. There have been no disclosures in the art prior to ourinvention herein with respect to the utilization of the encapsulatingability of a dendrimer-based network, particularly wherein the dendrimeris a silicon-containing dendrimer based material. Such an inventionwould be unique for the reason that all known exclusively puredendrimers are either viscous liquids or amorphous solids.

In contrast, our invention relates to what is believed to be the firstdendrimer-based elastomer or plastomer prepared from a radially layeredcopoly(amidoamine-organosilicon) (PAMAMOS) dendrimer, or from a radiallylayered copoly(propyleneimine-organosilicon) (PPIOS) dendrimer, capableof functioning as (i) a nanoscopic sponge for the absorption and theencapsulation of various metal cations, and water soluble organicmolecules from their water solutions; and which is capable offunctioning as (ii) a nanoscopic reactor for various physical andchemical transformations of such encapsulated guest ions and moleculeswithin their elastomeric or plastomeric network. In either case, theresulting products represent novel nanoscopic organo-inorganiccomposites which contain organosilicon units as an integral part oftheir covalently bonded structure.

Products resulting from the modifications herein of these PAMAMOS andPPIOS networks have many unique applications among which are inpreparing elastomers, plastomers, coatings, sensors, smart materials,membranes, barriers, O-rings, gaskets, sealants, insulators, conductors,magnetic materials, release surfaces, absorbents, implants, sensors,indicators, and radiation sensitive materials. Additionally, because theformation of PAMAMOS and PPIOS networks can be performed in molds ofvarious configurations and designs, these silicon-containingdendrimer-based network composites can be fabricated into objects ofvarious shapes and sizes. This is a distinct benefit and advantage ofour invention over pure dendrimers, which as noted, are viscous liquidsor amorphous solids, and which possess no useful mechanical propertiesusually found for engineering polymeric materials.

BRIEF SUMMARY OF THE INVENTION

This invention relates to silicon-containing dendrimer-based networksprepared from radially layered copoly(amidoanrine-organosilicon)dendrimers (PAMAMOS) or other related dendrimers such as PPIOSdendrimers, having a hydrophilic interior and an organosilicon exteriorwhich can (a) complex and/or in any other way encapsulate metal cationsor elemental metals; (b) encapsulate inorganic or organometallicproducts formed by reaction of complexed metal cations with otherinorganic, organic, or organometallic reagents; and (c) encapsulatewater soluble organic or organometallic molecules delivered into thenetwork either by diffusion from the surrounding exterior, or byformation through chemical or physico-chemical transformations occurringwithin the network interior.

The preparation of PAMAMOS dendrimers and PAMAMOS based dendrimernetworks is described in our '143 application and in our '943application, respectively, which applications are incorporated herein byreference.

The properties of PAMAMOS or PPIOS dendrimer-based networks depend uponthe type and structure of the particular dendrimer precursor used intheir preparation. This includes (i) the type and size, i.e., thegeneration of its poly(amidoarnine) or poly(propyleneimine) interior;(ii) the type and size, i.e., the number of layers of its organosilicon(OS) exterior; (iii) the relative ratio of the PAMAM or PPI interior andOS portions of the PAMAMOS or PPIOS dendrimer; (iv) the type of covalentbonding by which the PAMAM or PPI and the OS portions are connected; and(v) the type of covalent bonding by which PAMAMOS or PPIOS dendrimersare connected into the network.

The unique architecture of PAMAMOS as well as PPIOS networks provides aviable avenue for (i) entrapping, encapsulating, or otherwise complexingvarious metal cations from water solutions of their salts; and for (ii)performing reactions with such cations that result in forming variouswater soluble or water insoluble inorganic products containing elementalmetals, metal oxides, metal sulfides, or other metal salts, which remainencapsulated within the network.

As a consequence of our invention, one skilled in the art is enabled toprepare various nanoscopic organo-inorganic composite materials in whicha dendrimer network functions as a matrix in which metal(s) or inorganicproducts can be dispersed, having domains of precisely controllednanoscopic size and predefined distribution, obtainable as films,sheets, coatings, membranes, or other shapes. Our invention also enablesone skilled in the art to selectively encapsulate water soluble organicor organometallic molecules in the hydrophilic network domain of theelastomeric dendrimer, or to selectively encapsulate water insolubleorganic and organometallic molecules in the hydrophobic network domainof the elastomeric dendrimer.

Some representative organic and organometallic molecules which may beencapsulated include pigments; dyes; indicators; light or radiationsensitizers; catalysts; electro-conductive materials; non-linear opticalmaterials; liquid crystalline materials; light emitting materials;fluorescent materials; phosphorescent materials; polymerizable monomers,polymerization initiating materials; biomedical materials;pharmaceutical products; biologically active or inactive materials;antiseptic materials; surface active agents; as well as reactive,non-reactive, functional, or non-functional compounds.

PAMAMOS or PPIOS networks containing encapsulated guest atoms ormolecules provide utility in chemistry; chemical engineering;biochemistry; biology; medicinal chemistry; materials science andengineering; surface science and engineering; catalysis; reactor design;physics; membrane or barrier science and engineering; interactions ofradiation and matter; cosmetics and personal care; agriculturalchemistry; electronic, optoelectronic and electrical science andengineering; polymer science and engineering; metallurgy; ceramicsscience and engineering; chromatographic techniques; water purification;nuclear waste treatment; chemical, biological or sensor materials; andin the harvest of rare earth metals.

These and other features, objects, benefits, and advantages of ourinvention will become apparent from a consideration of the detaileddescription.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1 is a schematic representation of a PAMAMOS or PPIOSdendrimer-based network where circles represent PAMAM or PPI portions ofthe base dendrimer.

FIG. 2 shows the structure of a polyamidoamine dendrimer, in particular,an EDA core, generation 1 (G1) dendrimer, used to make a PAMAMOSdendrimer-based network such as depicted in FIG. 1.

FIG. 3 shows the structure of a PAMAM repeating unit of an EDA core,Generation 1 dendrimer, of the type shown in FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION

Our invention relates in general to the preparation, characterization,and application of silicon modified poly(amidoamine) andpoly(propyleneimine) dendrimers. In our '143 application, we havedescribed the preparation and the surface properties of radially layeredcopoly(amidoamine-organosilicon) dendrimers; while in our '943application, we have described the preparation of PAMAMOS-baseddendrimer networks which contain hydrophilic and hydrophobic nanoscopicdomains.

This instant application describes the utilization of these PAMAMOS orPPIOS networks as (i) elastomeric or plastomeric nanoscopic molecularsponges for the selective, non-selective, reversible, or irreversibleabsorption and/or entrapment of various metal cations, elemental metals,and water soluble small organic molecules; and as (ii) confinednanoscopic reactors for physico-chemical transformations of encapsulatedspecies including the reduction of metal cations to elemental metals,the formation of metal oxides, metal sulfides, or other salts, thetransformation of entrapped organic molecules by chemical reactions, andthe formation of organometallic compounds by reactions of entrappedorganic substrates and metal cations.

We believe that except for Group I elements, all metal cations can beabsorbed and encapsulated by our PAMAMOS or PPIOS network sponges. Somerepresentative metal cations include by way of example Cu¹⁺, Cu²⁺, Fe²⁺,Fe³⁺, Au³⁺, Ag⁺, Rh³⁺, Ni²⁺, and Cd²⁺. Organic molecules can also beencapsulated, representative of which are C₃₇ H₂₇ N₃ O₃.2NaSO₃(methylene blue), C₁₅ H₁₅ N₃ O₂ (methyl red), and a green ink present inPilot Razor Point II pens. Other metal cations, organic molecules, andorganometallic water soluble molecules may also be encapsulated.

It is particularly important to note that to our knowledge, PAMAMOS andPPIOS networks as described in our '943 application, represent the firstdendrimer based products possessing any concrete, measurable, materialproperty such as a modulus of elasticity, a tensile strength, anextensibility, or a percent of elongation. By way of comparison, otherreported dendrimers and/or dendrimer-based products are viscous liquidsor amorphous solids.

Thus, in particular, and according to our invention in this application,PAMAMOS or PPIOS networks are used (i) as nanoscopic molecular spongesthat can absorb and encapsulate a wide variety of metal cations fromtheir water solutions; are used (ii) to retain the thusly absorbed metalcations for long periods of time both in the dry state and when immersedin water or in an organic solvent; and are used (iii) to reversiblyrelease and absorb once more any of the aforementioned entrapped metalcations into and from the surrounding media, provided an appropriatedriving force for the transport can be established.

This application also relates to PAMAMOS or PPIOS dendrimer-basednanoscopic molecular sponges that can absorb and encapsulate variouswater soluble organic molecules, among which can be named asrepresentative, organic dyes, monomers, initiators, catalysts, andpharmacologically active compounds. In addition, there is disclosedherein that PAMAMOS or PPIOS dendrimer-based networks are capable ofproviding a continual medium of regularly distributed nanoscopicreactors for carrying out redox reactions of the absorbed andencapsulated metal cations, converting them into elemental metals, othermetal salts, metal oxides, or metal sulfides, including those metalcations that are most difficult to dissolve otherwise.

Furthermore, these PAMAMOS or PPIOS dendrimer-based networks are capableof performing various physical or chemical transformations of absorbedand encapsulated water soluble organic molecules, which molecules may bemaintained as such either within the network, or which molecules may befurther used in reactions with similarly absorbed or encapsulated otherorganic reagents, metals or metal cations, providing an avenue for theformation of numerous organic or organometallic compounds and mixtures.

For purposes herein, a PAMAMOS or PPIOS network is intended to mean andto include crosslinked PAMAMOS or PPIOS dendrimers containinghydrophilic (PAMAM or PPI) and oleophilic (OS) nanoscopic domainsdistributed uniformly throughout its bulk. The size of the hydrophilicPAMAM or PPI domain is predefined by selection of the PAMAM or PPIdendrimer used in preparing the precursor PAMAMOS or PPIOS dendrimer.The relative mass ratio and size of oleophilic organosilicon (OS)domains is predefined by the number and structure of the organosiliconlayers built around the PAMAM or PPI dendrimer during the synthesis ofPAMAMOS or PPIOS network precursors, and is also predefined by the typeof crosslinking reagent (if any) used in the network forming reaction.The type and the length of crosslinking bonds connecting neighboringhydrophilic PAMAM or PPI domains is predefined by the type oforganosilicon surface groups on the PAMAMOS or PPIOS dendrimer used inthe crosslinking reaction, and is also predefined by the type ofcrosslinking reagent (if any) used in the network forming reaction.

As can be seen in FIG. 2, hydrophilic PAMAM domains contain tertiaryamine branch junctures and amide connectors which are strong ligatingsites for electrophilic ligands. As a result, such PAMAM domains imparta high local concentration of ligating sites to the PAMAMOS dendrimernetwork, and exert a high attractive potential toward electrophilicguests. This creates a strong driving force for their migration into thePAMAM domain of the network from outside the media.

This phenomenon is illustrated in examples which follow, and it has beendiscovered to be a property of these materials for any water solubleelectrophilic substrate regardless of the nature of the organic orinorganic substrate. Thus, the phenomenon relates not only to watersoluble electrophilic substrates described in our examples, but to otherwater soluble inorganic cations, as well as to charged or polarizedorganic and/or organometallic molecules.

It should be understood that the features described herein relative toour PAMAMOS dendrimers and their networks are expected to be exhibitedby networks prepared from their closely relatedpoly(propyleneimine-organosilicon) (PPIOS) dendrimers, and otherradially layered copolydendrimers containing a hydrophilic interior andan outer organosilicon layer(s).

PAMAMOS precursors are obtained from PAMAM dendrimers whose surface hasbeen partially or completely modified with functional organosiliconmoieties. Related precursors can also be prepared frompoly(propyleneimine) (PPI) dendrimers in the same way. Such precursorsare the subject matter of our '143 application. The synthesis of suchdendrimers with radially heterogeneous molecular compositions is basedon different combinations of hydrophilic and hydrophobic layers. Thus,the structural units combined in these dendrimers are (a) a watersoluble amidoamine repeat structure such as -- (CH₂)₂ --CO--NH--(CH₂)₂--N!═ or a water soluble poly(propyleneimine) repeat structure such as-- (CH₂)₃ N!═, and (b) a hydrophobic organosilicon structure.

The compositions are organized as a hydrophilic poly(amidoamine) orpoly(propyleneimine) interior with a hydrophobic organosilicon exteriorlayer. The nature of the organosilicon layer can be varied, as well asthe architectural parameters of the dendrimer structure itself,including the functionality of the core, length and functionality of thebranches, and the generation of each different layer, i.e., theirrelative thickness.

The general structure of such dendrimers and their formation can berepresented as shown below: ##STR1##

Some examples of preferred organosilicon modifiers are compounds such as(3-acryloxypropyl)methyldimethoxysilane,(3-acryloxypropyl)bis(vinyldimethylsiloxy)-methylsilane,iodomethyldimethylvinylsilane, chloromethyldimethylvinylsilane, as wellas other (3-acryloxypropyl)-functional silanes or otherhaloalkyl-functional silanes.

PAMAMOS dendrimers are functional, globular, nanoscopic macromolecules,having sizes ranging from about 1 to about 15 nm in diameter; molecularweights ranging from about 1,200 to 1,000,000; with a hydrophilic PAMAMinterior encapsulated in a covalently connected lyophilic (oleophilic,hydrophobic) organosilicon outer shell. As such, they can be used forthe controlled or uncontrolled preparation ofPAMAM-organosilicon-containing dendritic networks, when containingreactive silicon-functional groups at the outer surface.

The reactive silicon-functional groups at the outer surface include any(CH₃)_(3-z-y) W_(y) Si-moiety, where X and W represent reactive groups;z is 1, 2 or 3; and y is 0, 1, or 2. For purpose of the presentinvention, any reactive silicon-functional group X or W can be used,including for example, --NH₂, --NR₂, mercapto (--R'SH), vinyl(--HC═CH₂), allyl, hydrogen, halogen, acetoxy --O(O)CCH₃, ureido, andalkoxy or aryloxy --OR. R represents an alkyl group containing 1-6carbon atoms, or an aryl group such as phenyl; and R' represents thecorresponding alkylene or arylene groups. The alkoxy group --OR is mostpreferred, however. In addition, W can be either a reactive or anon-reactive group, in which case W is preferably different from --CH₃or --X.

Crosslinking of PAMAMOS or PPIOS dendrimers into dendrimer-basednetworks can be achieved by any number of different types of reactions,including for example:

(1) catalyzed addition reactions such as hydrosilation or thioladdition, in the case of .tbd.SiCH═CH₂, .tbd.Si--CH₂ --CH═CH₂,.tbd.Si--R--SH, or .tbd.SiH surface functionalized dendrimers;

(2) self-catalyzed reactions such as hydrolysis with moisture or water,in the case of .tbd.SiCl and .tbd.Si--OR surface functionalizeddendrimers;

(3) non-catalyzed addition reactions such as Michael Addition; and

(4) condensation reactions.

The crosslinking may be performed with or without one or more addedreactants, such as small molecular or oligomeric (i) difunctionalreagents A₂, (ii) trifunctional reagents A₃, (iii) polyfunctionalreagents A_(x) where x is 4 or more, or (iv) by simply using moisturefrom the atmosphere, or intentionally added water. Representative A₂,A₃, and A_(x) reagents are for example, organohalosilanes,tetrahalosilanes, organosilanols, organo(organooxysilanes) such asdialkoxysilanes and trialkoxysilanes, organo-H-silanes,organoaminosilanes, organoacyloxysilanes such as acetoxysilanes,organosilsesquioxanes, ureido-substituted silanes, vinyl-substitutedsilanes, and allyl-substituted silanes. Corresponding organic ororganometalic compounds can also be employed.

Obtained elastomers are clear, highly transparent materials, exhibitinglow glass temperature (T_(g), and high thermal and thermo-oxidativestability. The exact values of these property parameters will depend ofcourse on the PAMAM or PPI dendrimer and the organosilicon reagent used;their relative content in the resulting PAMAMOS or PPIOScopolydendrimer; the number of built outer organosilicon layers; and thetype and relative amount of reagents A₂, A₃, and A_(x). Their uniqueinterior structure provides evenly distributed hydrophilic domains ofprecisely controlled nanoscopic sizes, which are covalently connectedwithin oleophilic and elastomeric organosilicon matrix, as can be seenin FIG. 1.

The elastomers are (i) mechanically stable; (ii) they show uniqueseparation and swelling characteristics; (iii) they can be obtained asthin films, membranes, or coatings having non-stick surfaces; (iv) theycan be molded into various other shapes; and (v) they can be compoundedwith various additives including fillers, antioxidants, and othermaterials commonly employed in the preparation of silicone elastomers.

The following examples describe methods for utilizing dendrimer basednanoscopic sponges; and methods for preparing various nanoscopicmolecular composites from dendrimer based networks and inorganic,organic or organometallic agents. These examples describe, inparticular, (a) the absorption and encapsulation of various metalcations; (b) the absorption and encapsulation of various water solubleorganic molecules; and (c) the transformation of encapsulated metalcations, including formation of elemental metals by reduction of thecorresponding metal cations encapsulated within the networks, andformation of metal oxides and metal sulfides from corresponding metalcations encapsulated within the dendrimer based network.

In all of the following experiments describing the preparation ofvarious metal-PAMAMOS network nanoscopic composites, preformed disks ofPAMAMOS network films were cut into smaller pieces (referred to below assamples), and then used as described in the example. The samples werealways hydrophobic in the beginning of the treatment and floated on thesurface of the aqueous salt solution employed. In all cases, treatmentwith a metal salt solution changed both the surface characteristic andthe density of the sample, as these usually spontaneously submergedunder the surface of the salt solution by the end of the respectiveprocedure.

EXAMPLE 1

Preparation of PAMAMOS dendrimers by modification of generation 3 (G3)EDA core PAMAM dendrimer with (3-acryloxypropyl)methyldimethoxysilane

All glassware used in this synthesis was first dried overnight in aheating oven and then assembled while still hot. A three-necked roundbottomed reaction flask was equipped with a nitrogen inlet, a stopper,and a condenser with another stopper at the top. The apparatus wasevacuated using a vacuum pump, and dried with a heat-gun using severalnitrogen-vacuum purging cycles. After cooling the apparatus to roomtemperature, it was filled with predried-nitrogen which had been passedover Drierite, and the glass stopper was replaced under a strongcounter-stream of dry-nitrogen by a rubber septum. A rubber balloon wasplaced on top of the condenser to allow control of slight overpressuresin the assembly. Syringes were also dried overnight in the oven and keptin a desiccator until used. A dendrimer placed in a flask waslyophilized overnight under high vacuum, and 2.08 g (0.30 mmol; 19.32mmol of --NH groups) of dendrimer were obtained. The flask was flushedwith dry-nitrogen, and the stopcock was replaced by a rubber septum. Tothe dendrimer, 19 mL of anhydrous methanol was added via a syringethrough a rubber septum, and when the dendrimer had dissolved, theobtained solution was transferred with another syringe to the apparatus.To this solution, 5.5 mL (23.18 mmol; 1.2 excess relative to --NHgroups) of (3-acryloxypropyl)methyldimethoxysilane H₂ C═CHCOO(CH₂)₃Si(OCH₃)₂ CH₃ was added, and the mixture was stirred under nitrogen atroom temperature for the entire duration of the reaction time. The % ofdendrimer surface modification was determined by ¹ H Nuclear MagneticResonance (NMR). For this determination, about 1 mL aliquot of thereaction mixture was used. The sample was removed with a syringe andtransferred into another two-necked round bottomed flask equipped with arubber septum and nitrogen inlet. Methanol was evaporated under vacuumand replaced with 0.7 mL of deuterated chloroform (CDCl₃). The resultingPAMAMOS dendrimer was stable as long as it was kept in an anhydrousenvironment. To complete the synthesis, chloroform (5 mL portions) wasadded to the reaction mixture initially every 24 hours, then every otherday after 3 days. After five days of total reaction time, the entiresolvent containing mixture was evaporated under vacuum, and the solventwas replaced by 9 mL of pure chloroform. A summary of the changes insolvent composition is provided in Table 1, together with the % of --NHdendrimer surface modification.

                  TABLE 1    ______________________________________    Preparation of PAMAMOS dendrimer from    Generation 3 EDA core PAMAM dendrimer    Reaction           Total volume                  % modifi-    Time   of solvent                     %MeOH/%CHCl.sub.3                                  c.sub.-NH groups                                         cation of    (days) (mL)      (v/v)        (mol/L)                                         -NH groups    ______________________________________    0      19        100/0        1.02   0    1      18        100/0        1.02   77.6    1      23        78/22        0.8    --    2      22        78/22        0.80   83.4    2      27        64/36        0.65   --    3      26        64/36        0.65   85.1    3      31        54/46        0.55   --    5      30        54/46        0.55   83.7    5      19          0/100      0.87   --    6      18          0/100      0.87   87.6    7      17          0/100      0.87   87.0    10     16          0/100      0.87   87.4    ______________________________________

At 87% NH substitution, ¹ H NMR in CDCl₃ showed the following: 0.02 ppm(s; .tbd.Si--CH₃); 0.52 ppm (m; --CH₂ --Si.tbd.); 1.61 ppm (m;--COO--CH₂ --CH₂ --CH₂ --Si.tbd.); 2.4-3.6 ppm (PAMAM dendrimerprotons); 3.40 ppm (s; .tbd.Si--O--CH₃); 3.94 ppm (t; PAMAM-COO--CH₂);4.02 ppm (t, CH₂ ═CH--COO--C₂ --); 5.68-6.32 ppm (d+dxd+d; CH₂═CH--COO--). ¹³ C NMR in CDCl₃ showed the following: --6.18 ppm(.tbd.Si--CH₂); 8.89 ppm (--CH₂ --Si.tbd.); 21.82 ppm (--COO--CH₂ --CH--CH₂ --Si.tbd.); 32.37 ppm (═N--CH₂ --CH₂ --COO--(CH₂)₃ --Si.tbd.);33.54 ppm (--CH₂ --CO--NH--); 34.75 ppm (--NH--CH₂ --CH₂ CH₂--COO-(CH₂)₃ --Si.tbd.); 37.10 and 37.29 ppm (--CO--NH--CH₂ --); 38.76ppm (--CO--NH--CH₂ --CH₂ --NH--(CH₂)₂ --COO--); 44.43 ppm (--CO--NH--CH₂--CH₂ --NH--(CH₂)₂ --COO--); 48.37 ppm (--NH--CH₂ --CH₂ --COO--(CH₂)₃--Si.tbd.); 48.92 ppm (--CO--NH--CH₂ --CH₂ --N--((CH₂)₂ --COO--)₂);49.54 ppm (--CO--NH--CH₂ --CH₂ --N═); 49.89 ppm (.tbd.Si--O--CH₃); 51.33ppm (═N--CH₂ --CH₂ --COO--); 52.20 and 52.60 ppm (═N--CH₂ --CH₂--CONH--); 66.31 ppm (═N--(CH₂)₂ --COO--CH₂ --); 128.32 and 130.18 ppm(CH₂ ═CH--); 172.21 and 172.31 ppm (--CH₂ --CH₂ --COO-- and --CO--NH--)and the unreacted acrylate reagent: -6.18 ppm (.tbd.Si--CH₃); 8.89 ppm(--CH₂ --Si.tbd.); 21.82 ppm (--COO--CH₂ --CH₂ --CH₂ --Si.tbd.); 49.89ppm (.tbd.Si--O--CH₃); 66.36 ppm (CH₂ ═CH--COO--CH₂ --); 128.32 and130.18 ppm (CH₂ ═H--); and 165.92 ppm (CH₂ ═CH--COO--).

EXAMPLE 2

Preparation of PAMAMOS dendrimer-based network containing lyophilicorganosilicon and hydrophilic poly(amidoamine) nanoscopic domains

A PAMAMOS dendrimer obtained as described in Example 1 after 24 hours ofreaction time having on average 84.5 methoxysilyl- end-groups permolecule was used for network preparation. 1 mL of the reaction mixture(composed of 0.015 mmol of dendrimer and 0.5 mmol of(3-acryloxypropyl)methyldimethoxysilane in 1 mL of methanol) waswithdrawn from the reactor, poured into an open aluminum pan, and leftexposed to atmospheric air loosely covered with a piece of aluminum foilto prevent contamination with dust. In contact with atmosphericmoisture, and in the presence of the basic PAMAM dendrimer interior,hydrolysis of the methoxysilyl-surface groups took place slowly, withmethanol by-product and solvent slowly evaporating. To monitor thecourse of this occurrence, the pan containing the sample wasperiodically weighted, until after about 5 days of total reaction time,when no further change of its weight could be detected. Thermalproperties of the obtained network sample were examined by DifferentialScanning Calorimetry (DSC), and by Thermogravimetric Analysis (TGA)under nitrogen. DSC analysis was performed from -20° C. to 100° C. at aheating rate of 10° C./minute, while TGA was performed by heating fromroom temperature (20-25° C.) to 1,000° C. at a heating rate of 20°C./minute. Glass temperature (Tg) was found at -7° C. after one monthafter preparation. TGA showed no weight loss until about 200° C., abovewhich two maxima in the thermograms were observed at 290 and 380° C.Weight loss at 290° C. was 17% of the original weight. Weight loss at380° C. was 71% of the original weight.

EXAMPLE 3

Permeability of a PAMAMOS dendrimer-based network to a water solution ofmethylene blue

A disc cut out of the PAMAMOS network sample synthesized in Example 2was placed in a filter holder attached to a syringe, and the wholeassembly was connected to a vacuum bottle. A solution of methylene bluein water (concentration=2.71×10⁻³ mol/L) was introduced into thesyringe, and a partial vacuum was applied to the vacuum bottle. In thebeginning, methylene blue permeated the membrane as indicated by bluedrops passing through the filter assembly, but then the membrane becameimpermeable to further flow. Upon opening the filter holder it wasobserved that the originally colorless, completely transparent membraneturned slightly blue during this experiment. The color could not bewashed away by rinsing the membrane several times in water, and when itwas attempted to reuse the blue film, it was found to be waterimpermeable. This was a clear indication that the hydrophilic methyleneblue had been encapsulated within the PAMAM domains of the network, thuspreventing further permeation of even water molecules.

EXAMPLE 4

Encapsulation of methylene blue in the PAMAMOS dendrimer-based networkof Example 2

A solution of methylene blue in water was prepared, and a sample of thePAMAMOS network prepared in Example 2 was immersed in the solution forabout 24 hours. The obtained sample was blue, and the colorationremained even after several repeated cycles of rinsing and immersion inwater.

EXAMPLE 5

Encapsulation of methyl red in the PAMAMOS dendrimer-based network ofExample 2

A solution of methyl red in acetone was prepared, and a sample of thePAMAMOS network prepared in Example 2 was immersed in the solution forabout 24 hours. The obtained sample was orange, and the colorationremained present even after several repeated cycles of rinsing andimmersion in water or acetone.

EXAMPLE 6

Encapsulation of green ink in the PAMAMOS dendrimer-based network ofExample 2

Green ink obtained from a Pilot Razor Point II pen was dissolved inwater, and a sample of the PAMAMOS network prepared in Example 2 wasimmersed in the solution for about 24 hours. The obtained sample wasbright green, and the coloration remained even after several repeatedcycles of rinsing and immersion in water.

EXAMPLE 7

Preparation of copper (II)--PAMAMOS dendrimer-based network nanoscopiccomposite

A sample of the PAMAMOS network prepared in Example 2 (21.84 mg) wasimmersed in a solution of copper sulfate in water concentration (c)=0.44mol/L! for about 16 hours. The sample turned bright blue during thistreatment, and its coloration remained even after several cycles ofrinsing or immersion in pure water for several days. The sample wasdried overnight under vacuum, and its weight was determined to be 24.00mg. Its thermal properties were examined by DSC and TGA under nitrogen.DSC was performed from -100° C. to 100° C. at a heating rate of 10°C./mn, and TGA was performed from room temperature to 1,000° C. at aheating rate of 20° C./mn. The sample showed a Tg of 44.6° C. and a twostep degradation process, with the maxima in weight loss at 275° C.(weight lost in this step was 15% of the original), and at 360° C. (59%of the original weight lost), respectively. A weight loss started atabout 75° C., showed a maximum at 146° C. and totaled about 2.6% of theoriginal weight. This weight loss was not related to network stability,but represented liberation of water trapped in the hydrophilic domainsof the sample.

EXAMPLE 8

Release of copper (II) from the copper (II)-PAMAMOS dendrimer-basednetwork nanoscopic composite of Example 7

A sample of the PAMAMOS network containing copper (II) in Example 7 wasimmersed in a 0.1 N solution of HCl in water for about 20 hours, takenout from the acid, rinsed several times with water, and immersed inwater for another several hours. This treatment resulted in completediscoloration of the sample, which upon completion of the procedure,appeared the same as the original sample obtained in Example 2. Thediscolored sample was dried overnight under partial vacuum and subjectedto DSC from -60° C. to 80° C. at a heating rate of 10° C./mn to show aTg of 28° C.

EXAMPLE 9

Preparation of copper (I)-PAMAMOS dendrimer-based network nanoscopiccomposite

A sample of the PAMAMOS network of Example 2 was immersed for about 24hours in a green saturated solution of copper (I) chloride in water.When it was removed, the sample was blue-green, and this colorationremained even after several cycles of rinsing by and immersion in purewater.

EXAMPLE 10

Preparation of iron (II)-PAMAMOS dendrimer-based network nanoscopiccomposite

A sample of the PAMAMOS network of Example 2 was immersed in a saturatedsolution of iron (II) sulfate in water for about 24 hours. When it wasremoved, the sample was yellow and no longer transparent. The colorationremained even after several cycles of rinsing by and immersion in water.After drying overnight in partial vacuum, the sample showed a Tg of 66°C. when examined by DSC from -50° C. to 100° C. at a heating rate of 10°C./mn.

EXAMPLES 11a TO 11d

Preparation of a platinum (O)-PAMAMOS nanoscopic composite

EXAMPLE 11a

Preparation of a PAMAMOS dendrimer having vinylsilyl-su face groups

3.66 g (0.53 mmol, 33.90 mmol of --NH groups) of a generation 3 EDA corePAMAM dendrimer which had been lyophilized overnight, was placed in around-bottom three-neck reaction flask equipped with a stopper, a TEFLONcoated magnetic stirring bar, and a vertical condenser with a nitrogeninlet at its top, and dissolved in 34.5 mL of N,N-dimethyl formamide(DMF). Vinyl(chloromethyl) dimethylsilane H₂ C═CH(ClCH₂)Si(CH₃)₂ (6.1mL; 40.45 mmol) and sodium bicarbonate (4.03 g) were added, and themixture was stirred and heated under nitrogen atmosphere for six days.An aliquot of the obtained product was dissolved in deuterated methanol(CD₃ OD), centrifuged and analyzed by ¹ H NMR. This analysis showed that85% of the original --NH surface groups had been modified, and that theobtained dendrimer contained on average 54.4 vinyl groups per molecule.The salts were filtered from the reaction mixture, and the filtrate wasdialyzed, first in a 50/50 methanol/water mixture, and then in puremethanol. At the end of this procedure, methanol was evaporated, and theobtained dendrimer was dried under a partial vacuum.

EXAMPLE 11b

Attempt at hydrosilation of the PAMAMOS dendrimer of Example 11a

A hydrosilation reaction was attempted to convert the dendrimer ofExample 11 a into its triethylsilyl-homologue in the usual manner. Forthis reaction, 0.79 g. (0.064 mmol, 3.5 mmol of vinyl groups), of thePAMAMOS dendrimer of Example 11a were placed in a two-neck round-bottomflask equipped with a stopper, a TEFLON® coated magnetic stiring bar,and a vertical condenser having a nitrogen inlet at its top. 0.03 mL ofplatinum (Pt) catalyst (a 0.3% by weight solution of platinumdivinyltetramethyldisiloxane complex in p-xylene) was added, followed byfreshly distilled triethylsilane (C₂ H₅)₃ SiH (0.67 mL; 0.49 g; 4.2mmol) and 10 mL of tetrahydrofuran (THF). The reaction mixture wasstirred and heated at 40° C. for 7 days under nitrogen, then at 60° C.for another 3 days. Because Fourier-Transform Infrared SpectroscopyF(TIR) and ¹ H NMR showed no reaction commencing after this treatment,another portion of 0.16 mL (1 mmol) of triethylsilane and 0.03 mL of Ptcatalyst were added after 9 days of total reaction time. The reactionmixture was then purified by dialysis in acetone, and after evaporationof the solvent, the obtained sample was dried overnight under vacuum,diluted in CDCl₃, and analyzed by ²⁹ Si NMR. Two peaks were observed,indicating unreacted --CH₂ Si(Me)₂ (CH═CH₂) groups at --8.69 ppm, and asilicone grease used in assembling the apparatus at -21.94 ppm. Nosignal resulting from the modification of the vinylsilyl-startingdendrimer could be found. This shows that the expected hydrosilationreaction did not occur, and this is due to the withdrawal of platinumcatalyst from the reaction mixture by complexation of the platinum (0)by the PAMAM interior of the PAMAMOS dendrimer.

EXAMPLE 11c

Preparation of a PAMAMOS dendrimer having vinylsilyl-surface groups

Vinyl(chloromethyl)dimethylsilane (7.2 mL; 6.54 g; 48.54 mmol), sodiumiodide (8.02 g; 53.4 mmol; NaI!/ ClR!=1.1), 15-Crown-5 ether ##STR2##(0.48 mL; 0.53 g; 2.43 mmol, 5%/ --Cl!), and DMF (10 mL), wereintroduced under nitrogen into a round-bottomed reaction flask equippedwith a mechanical stirrer and a vertical condenser having a nitrogeninlet at the top. The reaction mixture was stirred and heated at 60° C.overnight. In another flask, a Generation 3 EDA core PAMAM dendrimerhaving 32 --NH₂ surface groups was lyophilized from methanol. Afterkeeping the dendrimer under reduced pressure overnight, 4.37 g (0.63mmol; 40.45 mmol of --NH) of a thusly obtained crispy solid wasdissolved in 30 mL of DMF and added to the reaction mixture, followed by6.14 g of sodium bicarbonate. The reaction mixture was heated to 80° C.,and from time to time, samples were taken for ¹ H NMR analysis, whichwas used to monitor the progress of the reaction. Stirring and heatingwere stopped after 13 hours, when complete modification of the --NHgroups had been achieved. The obtained mixture was filtered, and thefiltrate was dialyzed (Spectra/Por 7; MWCO 3500), first in awater/methanol mixture, and then in pure methanol. The isolated PAMAMOSdendrimer product was dried under vacuum overnight. Its analysis showedthat the starting PAMAM dendrimer had been 93% modified. 4.87 g of thePAMAMOS dendrimer were obtained after purification, a 60.5% yield.

EXAMPLE 11d

Preparation of a PAMAMOS dendrimer having triethylsilyl-surface groupsby hydrosilation of the PAMAMOS dendrimer of Example 11c

0.76 g (0.059 mmol, 3.54 mmol of vinylsilyl- groups) of the PAMAMOSdendrimer of Example 11c was lyophilized in a one-neck round-bottomflask overnight from methanol. The lyophilized dendrimer was thendissolved in 3 mL of ethylene glycol diethylether which had been driedover calcium hydride, triethylsilane (0.68 mL; 0.49 g; 4.25 mmol), andan excess of platinum catalyst (0.3% by weight platinum as a solution ofa platinum-divinyltetramethyldisiloxane complex in p-xylene; 0.1 mL;i.e., the same catalyst used in Example 11b). This amount of catalystwas large enough to saturate all potential complexation sites of thePAMAM interior of the PAMAMOS dendrimer with one Pt (0) equivalent forevery 6 PAMAM nitrogens introduced in the flask. The reaction mixturewas stirred under nitrogen at 100° C. for 41 hours. After that time, asample of the mixture was withdrawn, dissolved in CDCl₃, and analyzed by¹ H NMR. Only a small amount of unreacted vinyl groups was observed,clearly indicating that the reaction had been successfully performed.The obtained dendrimer was no longer soluble in methanol, but it waseasily soluble in THF or chloroform, and was purified by dialysis fromTHF.

EXAMPLE 12

Preparation of rhodium (III)-PAMAMOS dendrimer-based network nanoscopiccomposite

A sample of the PAMAMOS dendrimer-based network of Example 2 wasimmersed in a deep red water solution of 100 mM of rhodium chloride(RhCl₃) for about 16 hours. The sample developed a dark yellow color dueto encapsulation of Rh(OH)₃, and the color did not change afterimmersion in a dilute hydrazine (H₂ NNH₂) solution. For example, it isknown that rhodium (III) chloride exists in the form of a mixedaqua-complex between Rh(H₂ O)₆ !³⁺ Cl₃ and RhCl₃ when dissolved inwater. These complexes are soluble only in acidic media, because thesolubility constant (K_(sp)) of Rh(OH)₃ is only about 1×10⁻²³. Thus,upon complexation from a dilute aqueous solution in the form of RhN₄ Cl₄!⁻, these complexes hydrolyze within the PAMAM interior, and lose HCl tothe tertiary nitrogens present in the PAMAM interior, and are trapped asRh(OH)₃.

EXAMPLE 13

Preparation of copper (II) sulfide-PAMAMOS dendrimer-based networknanoscopic composite

A sample of the PAMAMOS dendrimer-based network of Example 2 wasimmersed in a 10 mM copper (II) acetate soluti6n and soaked for about 16hours. The sample developed a blue coloration indicating complexation ofcopper (II) ions by the nitrogen ligating sites of the PAMAMOS dendrimerhydrophilic interior. The sample was rinsed with water, wiped dry with apaper towel, and placed in a scintillation vial. The vial was flushedwith nitrogen, filled with hydrogen sulfide gas, capped, and sealed witha paraffin. After 8 hours, the sample developed a light brown color,indicating formation of copper sulfide within the dendrimer basednetwork.

EXAMPLE 14

Preparation of nickel (II) sulfide-PAMAMOS dendrimer-based networknanoscopic composite

A sample of the PAMAMOS dendrimer-based network of Example 2 wasimmersed in a 10 mM nickel (II) acetate solution and soaked for about 16hours. After completion of this treatment, the sample was rinsed withwater, wiped dry with a paper towel, and placed in a scintillation vial.The vial was flushed with N₂, filled with H₂ S gas, capped and sealedwith paraffin. After 8 hours, the sample developed a dark gray color,indicating formation of nickel sulfide within the dendrimer basednetwork.

EXAMPLE 15

Preparation of cadmium (II) sulfide-PAMAMOS dendrimer-based networknanoscopic composite

A sample of the PAMAMOS dendrimer-based network of Example 2 wasimmersed in a 10 mM cadmium (II) acetate solution and soaked for about16 hours. After completion of this treatment, the sample was rinsed withwater, wiped dry with a paper towel, and placed in a scintillation vial.The vial was flushed with N₂, filled with H₂ S gas, capped, and sealedwith paraffin. After 16 hours of this treatment, the sample remainedtransparent, but developed a yellow color, indicating the formation ofcadmium sulfide nanoparticles within the dendrimer-based network. Anultraviolet (UV-visible) spectrum of the sample indicated a cutoff at520-530 nm. Since the particle size of cadmium sulfide is proportionalto the spectral cutoff, it was estimated that the particle size ofcadmium sulfide in this example was between 5-10 nm (50-100 Å).

EXAMPLE 16

Preparation of copper (0)-PAMAMOS dendrimer-based network nanoscopiccomposite

A sample of the PAMAMOS dendrimer-based network of Example 2 wasimmersed in a 10 mM copper (II) acetate solution and soaked for about 16hours. The sample became blue during this treatment, indicatingcomplexation of copper (II) ions by the nitrogen ligating sites of thePAMAMOS dendrimer hydrophilic interior. After completion of treatment,the sample was rinsed with water and wiped dry with a paper towel. Uponsubsequent immersion in a 100 mM aqueous hydrazine solution, the sampledeveloped a characteristic metallic copper color, indicating formationof a metallic copper dendrimer-based network nanoscopic composite.

EXAMPLE 17

Preparation of gold (0)-PAMAMOS dendrimer-based network nanoscopiccomposite

A sample of the PAMAMOS dendrimer-based network of Example 2 wasimmersed in a yellow solution of 40 mg of gold trichloride acidH(AuCl₄).XH₂ O! in 10 mL of water and soaked for 30 min. During thistreatment, the sample developed a dark wine-red color, indicatingencapsulation of gold III hydroxide Au(OH)₃ !, which spontaneouslydecomposes under basic conditions or when exposed to light. Uponsubsequent immersion into a 100 mM aqueous hydrazine solution, thesample instantaneously turned dark-red. It is noted that Au (III)chloride exists in an HCl solution as an H(AuCl₄) complex. Uponextraction from such a solution by complexation in the interior of adendrimer, this H(AuCl₄) complex hydrolyzes, and loses HCl to thetertiary nitrogens, and is entrapped as Au(OH)₃, which subsequentlydecomposes. An UV-visible spectrum of the sample showed a cutoff above700 nm. Since the corresponding cutoff for gold nanoparticles is about550 nm, this observation indicated that the bulk of the network samplehad an interconnected channel structure.

EXAMPLE 18

Preparation of silver (0)-PAMAMOS dendrimer-based network nanoscopiccomposite (i.e., an elastomeric silver mirror)

A sample of the PAMAMOS dendrimer-based network of Example 2 wasimmersed in a 100 mM silver trifluoromethanesulfonate (CF₃ SO₃ Ag)solution and soaked for 16 hours in the dark. Upon completion of thistreatment, the sample was rinsed with water and wiped dry with a papertowel. One end of the sample was then treated with a drop of a 100 mMaqueous hydrazine solution as reducing agent, while the other end wastreated simultaneously with a drop of 0.1 M Na₂ S₂ O₃ solution. Asexpected, the sodium thiosulfate solution removed encapsulated silvercations and made its end of the sample clear and transparent, whereasthe other end treated with the reducing agent turned to a silver mirrorwhich retained the flexibility of the original sample.

Other variations may be made in compounds, compositions, and methodsdescribed herein without departing from the essential features of ourinvention. The forms of invention are exemplary only and not intended aslimitations on their scope as defined in the appended claims.

We claim:
 1. A composition comprising (i) a metal cation, (ii) a metalsalt, (iii) a metal oxide, (iv) an elemental metal, (v) a water solubleorganic molecule, or (vi) a water soluble organometallic molecule,adsorbed, absorbed, or encapsulated in a dendrimer-based network havinghydrophilic and hydrophobic nanoscopic domains, the dendrimer-basednetwork comprising a crosslinked product of a radially layeredcopolydendrimer having a hydrophilic interior, and a hydrophobicorganosilicon exterior terminated with reactive end groups, thecopolydendrimer being prepared by reacting a hydrophilic dendrimerhaving --NH₂ surface groups, with an organosilicon compound, in thepresence of a solvent.
 2. A composition according to claim 1 in whichthe reactive end groups of the copolydendrimer are hydrolyzable groups,and the copolydendrimer is crosslinked to form a dendrimer-based networkhaving hydrophilic and hydrophobic nanoscopic domains.
 3. A compositionaccording to claim 1 in which the copolydendrimer is crosslinked bycontacting the copolydendrimer with a crosslinking agent selected fromthe group consisting of low molecular weight or oligomeric (i)difunctional reagents, (ii) trifunctional reagents, and (iii)polyfunctional reagents.
 4. A composition according to claim 3 in whichthe crosslinking agent is selected from the group consisting oforganohalosilanes, tetrahalosilanes, organosilanols,organo(organooxysilanes), organo-H-silanes, organoaminosilanes,organoacyloxysilanes, organosilsesquioxanes, ureido-substituted silanes,vinyl-substituted silanes, and allyl-substituted silanes; and thehydrophilic interior of the copolydendrimer is selected from the groupconsisting of polyamidoamine and polypropyleneimine.
 5. A compositionaccording to claim 1 in which the reactive end groups on the hydrophobicorganosilicon exterior of the copolydendrimer are moieties conforming tothe formula (CH₃)_(3-z-y) X_(z) W_(y) Si--, wherein X represents thereactive end group; W is a reactive or non-reactive group different from--CH₃ or --X; y is 0, 1, or 2; z is 1, 2 or 3; and z+y is 1, 2, or
 3. 6.A composition according to claim 5 in which the reactive end group X isselected from the group consisting of --NH₂, --NR₂, --R'SH, --HC═CH₂,--CH₂ --CH═CH₂, hydrogen, halogen, --O(O)CCH₃, --NH(O)CNH₂, alkoxy, andaryloxy; wherein R represents an alkyl group containing 1-6 carbon atomsor an aryl group; and R' represents an alkylene group containing 1-6carbon atoms or an arylene group; and the hydrophilic interior of thecopolydendrimer is selected from the group consisting of polyamidoamineand polypropyleneimine.
 7. A composition according to claim 1 in whichthe organosilicon compound is a (3-acryloxypropyl)-functional silane ora haloalkyl-functional silane.
 8. A composition according to claim 7 inwhich the organosilicon compound is(3-acryloxypropyl)methyldimethoxysilane,(3-acryloxypropyl)bis(vinyldimethylsiloxy)-methylsilane,iodomethyldimethylvinylsilane, or chloromethyldimethylvinylsilane.
 9. Acomposition according to claim 1 in which the metal cation is selectedfrom the group consisting of Cu¹⁺, Cu²⁺, Fe²⁺, Fe³⁺, Au³⁺, Ag⁺, Rh³⁺,Ni²⁺, and Cd²⁺.
 10. A composition according to claim 1 in which theelemental metal is Pt(O).
 11. A composition according to claim 1 inwhich the water soluble organic molecule and the water solubleorganometallic molecule is selected from the group consisting ofpigments, dyes, indicators, light sensitizers, radiation sensitizers,catalysts, electro-conductive materials, non-linear optical materials,liquid crystalline materials, light emitting materials, fluorescentmaterials, phosphorescent materials, polymerizable monomers,polymerization initiating materials, biomedical materials,pharmaceutical products, biologically active materials, biologicallyinactive materials, antiseptic materials, and surface active agents. 12.A composition according to claim 11 in which the water soluble organicmolecule is selected from the group consisting of C₃₇ H₂₇ N₃ O₃.2NaSO₃(methylene blue), C₁₅ H₁₅ N₃ O₂ (methyl red), and green ink.
 13. Amethod of making organic compounds, inorganic compounds, andorganometallic compounds, comprising reacting an organic reagent, aninorganic reagent, or an organometallic reagent, with the metal cationin the composition defined in claim
 1. 14. A method of making elementalmetals, metal oxides, metal sulfides, and other metal salts, comprisingreducing the metal cation in the composition defined in claim
 1. 15. Amethod of making metal oxides comprising oxidizing the metal cation inthe composition defined in claim
 1. 16. A method of making organiccompounds, organometallic compounds, and mixtures of organic compoundsand organometallic compounds, comprising reacting an organic reagentwith the water soluble organic molecule or the water solubleorganometallic molecule in the composition defined in claim
 1. 17. Amethod of recovering a metal cation or a mixture of metal cations fromwater comprising contacting water with a dendrimer-based network havinghydrophilic and hydrophobic nanoscopic domains, the dendrimer-basednetwork comprising a crosslinked product of a radially layeredcopolydendrimer having a hydrophilic interior, and a hydrophobicorganosilicon exterior terminated with reactive end groups, thecopolydendrimer being prepared by reacting a hydrophilic dendrimerhaving --NH₂ surface groups, with an organosilicon compound, in thepresence of a solvent.